Air-brake system.



P. WERTZ.

AIR BRAKE SYSTEM.

APPLICATION FILED JUNE 28,1913.

1 1 92,482. I Patented July 1916.

5 SHEETS-SHEET l- WITNESSES P. WERTZ.

AIR BRAKE SYSTEM. APPLICATION man JUNE 28. 1913.

' 1,192,482. I Patented July 25,1916.

5 SHEETS-SHEET 2.

WITNESSES INVENTOR W%%W f? P. WERTZ.

AIR BRAKE SYSTEM.

APPLICATION FILED JUNE 28, IBIS. 1 ,1 92,482. Patented July 25, 1916.

5 SHEETSSHEET 3.

nu nu nuioH FIG.8

HIHHIHHI Ill WITNESSES INVENTOR WW @Mwf WITNESSES INVENTOR PETER WERT Z,OF PITTSBURGH, PENNSYLVANIA.

AIR-BRAKE SYSTEM.

Specification of Letters Patent. Patented July 2 5, 1916.

' I Applicationfiled June 28, 1913. Serial No. 776,250. g

To all whom 2'25 may concern:

Be it known that 1, PETER Wnurz, a resident of Pittsbiiugh, in thecounty of Alleghe-ny and State of Pennsylvania, have invented a new anduseful Improvement in Air-Brake Systems, of which the following is aspecification.

. This invention relates to air brake systems, and its object, briefly,is to provide an air brake system in which the engineer has bettercontrol of the train and can secure better brake service than withexisting air brake systems, and by the use of less and simplerapparatus.

Generally stated, the invention comprises a system wherein the engineer,with a single brake valve, can apply and release the brakes on theengine and train either independently or in unison with one brake valve,as required; wherein the engine brakes are automatically applied in casea hose bursts or an emergency application is made; and also comprises aspecial arrangement and valve enabling the engine equipment to be usedin double heading or in case theengine is dead heading or without steamin the boiler, without the use of a special engine triple, distributingvalve or auxiliary reservoir.

In the accompanying drawings, Figure 1 is a diagrammatic view of theimproved system; Fig. 2 is a sectional view through the en gineers brakevalve, showing the same .in emergency position, the valve seat beingshown in section taken on the line AA, Fig. 8, and the rotary valve insection on the line BB, Fig. 16; Fig. 3 is a detail plan view of thesame, the top casing member being omitted, and showing the valve seat infull lines and the quadrant in dash lines; Fig. 1 is a plan view of therotary valve; Fig. 5 is a vertical section through the special doubleheading valve; Fig. 6 is a similar view through the brake cylinderexhaust valve; Fig. 7 is a section through a pressure controlling valve;Fig. 8 is a section through a reducing valve; Fig. 8f is a detailsection through the rotary valve on the line CC, Fig. 4; and Figs. 9 to16 are diagrammatic views showing the different positions of theengineers brake valve.

My system is particularly designed as an improvement upon the systemshown, described and claimed in the prior application of F. H.Dukesmith, for air brake system,

filed November 25, 1912, Serial N0; 733,430,,

and in some respects is similar thereto. As

illustrated in the drawings, it embodies the brake cylinder 8, allconnected up and operating in the usual way of automatic air brakesystems, such as the Westinghouse or New York Air Brake Companyssystems. The only difference from these systems so farv referred to isin the construction and function of the engineers brake valve 4:, aswill be hereinafter pointed out. 9 represents the engine brake cylindersand 10 the tender brake cylinder, which are. all connected by the pipe11 to the engineers brake valve 4:, for operation by straight air ordirect pressure when desired, as hereinafter described. The engineersbrake valve t has a casing comprising a lower portion 12 and an upperportion. 13, suitably secured together as is usual. The fiat upper faceof the lower portion 12 has rigidly secured thereto a valve seat 1 1,which preferably is a flat horizontal seat and is provided with thenecessary ports and openings for effecting the various functions of thevalve. As shown, said seat is provided with a port 15, communicatingwith a passage 16 to which the main reservoir pipe 3 is connected; :1.large arc-shaped port 17 having an end extension 17 and communicatingwith a passage to which the train pipe 5 is connected; a port 19communicating with the engine brake cylinder pipe 11, a small port 20and a larger port 21 cored through the casing and communicating with acored passage 19 leading to the port 19; a large exhaust port 25 leadingto the atmosphere; and a small exhaust port 25 also leading to theatmosphere. The lower portion of the casing is provided with a port 22communicating with a passage 23 leading to a pipe 24 connected to themain reservoir pipe 11, as hereinafter described. Cooperating with thevalve seat 14 is the rotary disk valve 26, which is provided on itslower face with the arc-shaped cavity 27, of considerable length, and inits body with a cored out arc-shaped passage 28, which opens on the faceof the disk next to the valve seat through three large ports 29, 30 and31. Extending entirely through the disk are an oval port 33 having alarge opening on the upper face of the valve, and a large port 34 havingan angular extension 34* on the valve seat face ofthe disk.

The upper part of the valve casing isprovided with a passage 35 leadingfrom the port 22 to a chamber above the rotary disk valve, so that thepressure above the rotary valve is always main reservoir pressureunreduced; Said disk is rotated by a handle 36 connected to the stem 37of a rotary member 38 mounted in the casing and having a suitableconnection with the disk, such as a key 39 fitting between ribslO on theupper surface of the disk. The handle is provided with the usualspring-pressed dog ll, cooperating with notches in the quadrant 4:2, allas is usual in engineers brake valves. The quadrantis provided withshoulders or notches'43, 44, 4:5, 46, 4:7, 48, 49 and 50 adapted toreceive the spring-pressed dog l-l'and indicating the various positionfor effecting the several operations and functions of the brake valve.

The engine and tender brake cylinders are exhausted through a specialvalve shown at 51. This comprises a suitable casing having therein achamber 52, in which works a piston or diaphragm 53, having a stem 54carrying two valves 55, 56 adapted to cooperate with oppositely dlsposedvalve seats 57 and 58. The chamber 52, on the upper side of the piston53, communicates with the pipe 11 leading from the brake cylinders tothe engineers brake valve. Between the valve seats 57 and 58, thechamber is provided with a side exhaust port or outlet 59. Valve 55seats toward the pipe 11 leading to the engineers brake valve, and valve56 seats in the opposite direction or away from said pipe 11. Chamber orspace 52 within the casing, at the opposite end of the valve from pipe11, communicates through a pipe or connection 60 with the pipe 11leading valve and the brake cylinder is located a reducing valve 62,hereinafter referred to more fully in detail. Chamber 52 of the exhaustvalve, between the piston 53 and valve 55, is open to the atmospherethrough a vent port 63. The valve seats 57, 58 are formed withcomparatively sharp edges and are of smaller diameter than the piston53, so that the latter is in effect a differential piston,

with a greater effective area on the upper or engineers'brake valve sidethan on the lower or brake cylinder side. The purpose of theexhaustvalve 51 is t control the exhaust from. the engine and tender brakecylinders. It is apparent that as long as pressure exists in the chamber52 above the piston 53, the piston will be forced downwardly, seatingvalve 56 against its valve seat 58 and closing the exhaust voutletnection 60, the non-return check valve 61 preventing flow of pressurethrough theside branch 11. Valve 56 therefore opens and establishescommunication between the brake cylinders and the exhaust outlet 59, and

closes valve 55, so that no air from the brake I cylinders exhauststhrough pipe 11 and the engineers brake valve. The brake cylinders arecharged with air through the pipe 11 leading from the engineers brakevalve and upon application of the brakes, the pressure.

valve 66 which'seats toward the engineers brake valve, being normallyheld to its seat by spring 67. On the engineers brake valve side of thepressure controller is a suitable piston or diaphragm 68, which eitherconnectedto or bears against the stem of valve 66. Regulating spring 69bears against this piston or diaphragm and tends to move the same in adirection to unseat the valve 66. The spring 69 is adjusted or regulatedby a screw 7 0, located in a side chamber 71.

If the main reservoir pressure is at, say 100 pounds, and the regulatingspring 6 is set at, say 70 pounds, this spring holds the check valve 66openuntil there is slightly more than 70 .pounds'pressure on theengineers brake valve side of the pressure controller, when the spring69 is overbalanced and the diaphragm 68 is forced away from valve 66 soas to permit said valve to be seated by its spring 67 and the mainreservoir pressure. As soon as the pressure in the train pipe fallsbelow 70 pounds the spring 69 pushes the diaphragm outwardly 'to, but isused in inverted position.

holds itopen until the brake pipe pressure builds up slightly above 7 0pounds.

In the operation of air brake systems on long trains where the trainpipe has considerable volume the front brakes of the train arefrequently let off, or fail to set, in serviceapplication, due totherestricted vent opening at the engineers brake valve and the forwardsurging of'the large volume of air in the train pipe, the latter causinga momentary increase of pressure at the forward end of the train pipeand either releasing the brakes as described or preventing them frombeing applied. In order to overcome this difficulty, Iutilize anequalizing accelerator valve 7 52, which is of the same type anddescription as the valve shown for this purpose in the prior Dukesmitliapplication hereinabove referred to. This valve is connected in thetrain pipe 5, as shown in the drawings.

represents a special valve for use in double heading or dead heading,and acting to automatically apply the'brakes in emergency or in case ahose bursts. This valve in most of its features, is identical with theequalizing accelerator valve 7 2 just referred The valves are, however,so nearly alike that the same patterns can be used in producing them,thereby decreasing the cost of installation.

The valve comprises a suitable casing 76 having therein a chamber 77 incommunication, through a pipe 78, with the main reservoir pipe 3 betweenthe pressure controlling valve 64 and the engineers brake valve. Chamber77 has communicating therewith a by-pass or passage which is controlledby a check valve 7 9 in position to close said passage, said passagecommunicating with a chamber 79 in the lower part of the casing, whichchamber is in direct communication with the train pipe 5. The chamber 77in the upper part of the valve casing communicates with the upper sideof a piston 80. This piston carries a graduating valve 81 havingportions of different diameters, as shown, and controlling the port 82which connects the chamber 83 above the piston with a passage leading toa pipe 84: communicating with pipe 11 at the upper end of the brakecylinder exhaust valve 51. The under face of the piston 80 is indirectcommunication with chamber 7 9 through ports in the plate 86. Anequalizing stem 87 held by spring 88 is located in contact with the stemof piston 80, said spring being under light tension when the valve isclosed.

The operation of this valve is as follows: The main reservoir pressurein pipe 3 is reduced. through the pressure controlling valve 6 to trainpipe pressure, so that in running position the pressure in the chamber83 above piston 80, which is in communication with" pipe 3 above thepressure controlling.

valve 64, is the same asthe train pipe pres sure-effective on the underside of piston Whenever the train pipe pressure 1s reduced suflicientlyfor the spring 88 to yield, say seven pounds, piston 80 moves downwardlyand opens the port 82, thereby admitting pressure from the mainreservoir pipe 3 into pipe 11 and to the engine brake cylinders, so thatif the engine is a second or following engine in double headingreduction of train pipe pressure by manipulation of the engineers brakevalve on the leading engine will automatically apply the engine andtrain brakes on the second or following engine.

Pipe S l is provided with a non-return check valve 90, seating towardvalve 75, to prevent back How through said valveofv brake cylinderpressure or pressure admitted to pipe 11. In double heading the cook 91in the train pipe connection 5 on the second or following engine isclosed, and on said engine the engineers brake valve is placed inrunning position, but slightly turned in the clockwise direction fromthe position shown in Fig. 12, so that port 29 in the valve seat isalmost lapped, having only a small opening to the cavity 28' andallowing a slight leakage to exhaustfrom the pipe 11 through theengineers brake valve. On the second or following engine the mainreservoir maintains the pressure of the engine brake cylinders bypressure admitted through pipe 84, and the main reservoir also maintainsthe slight leakage through the pipe 11, and said leakage is not rapid orlarge enough to decrease the pressure on the upper surface of the pistonin valve 51 so as to unseat said valve and produce an exhaust from thebrake cylinders. However, when train pipe pressure is increased bymanipulation of the en ginecfs brake valve on the leading engine, theincreased train pipe pressure becomes eifective in valve 75 on thesecond or following engine, and closes said valve so as to cutoffcommunication from the main reservoir through the valve 75 to the pipe84. This stops the supply of pressure to maintain the slight leakagefrom the pipe 11, so that said leakage immediatelybecomes effective andso reduces the pressure on the upper face of the piston in the valve 51as to permit said piston to rise and exhaust the brakes of the second orfollowing engine through the exhaust valve 51 in the usual manner.

Reducing valve 62 may be of the same construction and arrangement as thepressure controller 64, and is so shown in the drawings. It differs,however, in that chamber 92, in which is located the controlling spring93, is provided with a small vent port 92, and is in communicationthrough a small pipe 94c, with the. pipe 84: between the non-returncheck valve 90 and valve 75. The spring 93 is adjusted with heaviernormally open. Tn service application, or

, in light applications of the brakes, valve 62 acts as a reducing valveto reduce the pressure from, say pounds in the train pipe, to .45 poundsin the brake cylinder. In service applications the enginebrakes areapplied by direct or straight air pressure coming from the mainreservoir by way of pipe 11. The check valve prevents back flow of thispressure through the pipe 84. In service applications a reduction isalso made in train pipe pressure so that valve 75 opens and allowspressure to flow from the main reservoir into pipe '84. Pipe 94 is smallas compared to pipe 84 and chamber 92 is open to exhaust through therestricted vent 92*. Pressure can not therefore build up in chamber 92with sufficient rapidity to be effective on piston 95, and when thebrake cylinder pressure builds up. to the proper amount, say 45 pounds,it over-balances the spring 93 and allows spring 95 to close thereducing valve. When a heavy reduction is made in the train pipepressure, as in emergency applications, the engine brakes are appliedautomatically, without straight air. .Pipe 11 is cut off by theengineers brake valve and all of the air flows into the brake cylindersby way of valve 75. It flows in with such force and rapidity that aircan flow through pipe 94 and build up pressure in chamber 92 so thatpressure is equally effective on both sides of the piston 95, and valve62 is held open by the spring In emergency applications, therefore, fullmain reservoir pressure, except as reduced by valve 64 is admitted tothe engine brake cylinders.

The engineers brake valve has eight positions, as follows:

1. Train release position, shown in Fig. 9, and in which the brakehandle 36 is at the extreme left hand position with the dog 41 in thenotch 43 of the quadrant 42. In this position the arc-shaped cavity 27in the rotary valve 26 overlaps the ports 15 and 17 in the valve seat,so that main reservoir arc-shaped port 17, thereby giving an additionalsource of main reservoir pressure and produclng a quick release of thetriple valves onall of the cars. Oval port 33 partly over laps port 21,and unreduced main reservoir pressure therefore flows through the pipe11 to the engine brake cylinders and holds the engine and tender brakesapplied. The pressure also passes into the chamber 52 above the piston53', thereby forcing down said piston and seating valve 56and-preventing exhaust from the main reservoir or from the brakecylinders by way'of the exhaust valve 51. This position enables theengineer to either make an independent straight air application of theengine and tender brakes while the. train brakes are kept released, orit enables him to hold the engine and tender brakes appliedwhilereleasing the train brakes. This prevents pulling out the drawheads. t also enables the train brakes on a long train to be pumped offat a stop while holding the train with the engine brakes, so that thetrain can move as soon as the stop is over, without further delay. Torelease the engine brakes after this application has been made theengineer turns the handle 36 of his valve to running position,hereinafter described.

2. Straight air application position, shown in Fig. 10 In thispositionthe spring dog 41 of the brake valve handle engages notch '44 in thequadrant 42. Cavity27 overlaps ports 15 and17 in the valve seat, so thattram pipe pressure is maintained by the main reservoir. Extensions 54and 17 a have passed out of registration with each other.

Port 33 is fully over port 21 in the valve seat, so that full mainreservoir pressure is admitted from the chamber above the rotary valveto pipe 11 and the engine and tender brake cylinders. All other ports inthe 'valve are lapped or closed. This position enables the engineer tomake a full straight air application of the engine and tender brakes, sothat the slack in the train can be taken up before applying the trainbrakes. After applyingthe engine brakes the train brakes may be appliedby turning the handie of the valve to service position, hereinafterdescribed. The'engine brakes may be held applied after a straight airapplication by turning the valve to straight air or to maintenance lapposition.

3. Straight air lap position, shown in Fig. 11. In this position the dog41 of the brake valve handle engages notch 45 of the quadrant 42. Thearc-shaped cavity 27 overlaps ports 15 and 17 in the valve seat,

so that train pipe pressure is maintained by the main reservoir. Allother ports in the valve are lapped or closed, so that the en- 'gine andtender brakes, when applied, may be held without application. of thetrain brakes.

4. Running or full release position, shown in Fig. 12. In this positionthe dog 41 of the brake valve handle is in contact with and the brakeson all the cars are released. Ports 29 and 30, which communicate with 60into chamber 52 underneath piston 53 and valve 56 and lift the pistonand unseat valve 56 and also closing valve 55. The brake cylinderpressure consequently is prevented from returning to the pipe 11 andescapes at the exhaust port 59, thereby releasing the engine and tenderbrakes. This release can be gradual, as the brake valve handle can bemanipulated to exhaust mere puii's of air from pipe 11 through the smallport 20 and reduce the brake cylinder pressure pound by pound, asdesired.

5. Independent release position, shown in Fig. 13. In this position thespring dog 41 of the brake valve handle engages the notch 47 in quadrant42. Port 30 in the valve overlaps port 20, and port 31 overlaps theexhaust port 25. All other ports are blanked. In this position thepressure in pipe 11 and chamber 53 escapes to the atmosphere by way ofports 19, 20, 30 and 31, consequently opening the engine and tenderbrake cylinders to. exhaust through the eX- haustvalve. This is theposition assumed when it is desired to release the engine brakesindependently of the train brakes after application of the latter,either 1n service or in emergency position.

1 6. Maintenance lap position, shown in Fig. 1st. In this position ofthe valve the spring dog 11 of the brake valve handle engages the notch48 of the quadrant 42. In this position port 3% in the rotary valvepartly overlaps port 21 in the valve seat, thereby gradually supplyingmain reservoir pressure to pipe 11 and the engine and tender brakecylinders. This allows the brakes to go on very gradually and also takescare of leakage in the brake cylinders on the engine and tender.

7. Service application, shown in Fig. 15. In this position of the valvethe spring dog ll of the brake valve handle engages notch 19 of quadrant12. In this positlon of the valve one end of the cavity 27 in the rotaryvalve 26 overlaps the small service application exhaust port 25 in thevalve seat and the other end of said cavity overlaps port 17 in'theseat, so that in this position the train pipe is vented to theatmosphere, but at a moderate rate. The moderate reduction of pressurein the train pipe thereby produced causes all of the triple valvesthroughout the train to respond and set the brakes on the cars. Port 29also registers with main reservoir port 15, while port 31 registers withthe small port 20 in the valve seat. Port 34 also partly overlaps port21. Main reservoir pressure, therefore flows from two sources to thepipe 11 and to the engine and tender brake cylinders. The reduction oftrain pipe pressure also causes the piston 80 of the double headingvalve 76 to move downwardly and open valve 81, thereby establishingcommunication from the main reservoir pipe 3, pipe 78, valve and pipe84. to the engine brake cylinders. Valve 62 acts as a reducing valve,and when the pressure in the engine and tender brake cylinders builds upto, say 45 pounds, said valve closes. Pressure is also admitted to thechamber 52 above piston 53 of valve 51, thereby seating valve 56,whereby the engine and tender brake cylinders are held set in exactproportion to the amount of reduction from the train pipe.

8. Emergency position, shown in Fig. 16. This position is reached whenthe spring dog 41 of the brake valve handle engages notch 50 in thequadrant 42. In this position cavity 27 in the rotary valve overlapstrain pipe port 17 and the large exhaust port 25, thereby creating alarge opening from the train pipe to the atmosphere, with a rapid andlarge reduction of train pipe pressure and emergency application of thetrain brakes. All other ports are blanked. The rapid and large reductionof train pipe pressure evacuates chamber 79 below the piston 80, so thatsaid piston travels quickly downwardly with force sufiicient to overcomethe spring 88 and fully open the port 82. This admits a large volume ofair from the main reservoir pipe 3 to pipe 8 1, whence it flows by wayof valve 62 to the engine and tender brake cylinders. The same pressureis also effective through pipe 9th in the chamber 92 on the upper sideof the piston 96. The pressures on both sides of said piston are equaland the valve 92 is consequently held open by the spring 93, so thatfull pressure is allowed to flow to the engine and tender brakecylinders. Pressure is also effective in the chamber 52 above piston 53,thereby closing valve 56 and holding the engine and tender brakes set.After making an emergency application the engineer, by bringing thehandle back to maintenance lap position, can maintain the brake cylinderpressure on the engine and tender, regardless of brake cylinder leakage,or, if the brakes have been applied too severely, he may bring thehandle back to independent release position and partly release theengine brakes to prevent heating or flattening the engine tires.

After an emergency application there is .no pressure in the train pipe,and conse quently valve 75 remains open since its spring 88 is unable toovercome the reduced main reservoir pressure still effective on the topof piston 80, so that main reservoir pressure would normally continue toflow to the engine brake cylinders. brakes after an emergencyapplication the engineer closes the cook 98 in the pipe 78 between valve75 and pipe 3. This cuts out the main reservoir pressure from abovevalves 7 5 and 51. By placing the engineers brake valve in independentrelease position the pressure is exhausted from pipe 11, which allowsthe piston of the valve 51 to move over and thereby exhaust the enginebrake cylinders through valve 51. When the engine brake cylinders havebeen released cook 98 may be opened and the brake may then be operatedin the usual manner.

In double heading the handle of the brake valve on both the leading andall following r the brake cylinders. Pipe 11 on the second or followingengines is open to exhaust through the ports 20, 29, 30 and 25. Thiswill exhaust only the'air in pipe 11, since the check valve 61 preventsexhaust from the brake cylinders. As the air is exhausted from pipe 11it is rapidly replenished through the valve 75 since port 20 isrestricted, but there is no serious waste of air from the main reservoirand the exhaust is not large enough to sufficiently reduce the pressurein chamber 52 above the piston 53 to open the valve 56. The brakes areconsequently held applied. When train pipe pressure is increased bymanipulation of the brake valve on the leading engine, piston 80 on thesecond engine moves over and cuts off "communication between'the mainreservoir pipe 3 and pipe 84 leading to the brake cylinder pipe 11.Brake cylinder pipe 11 is, however, open to exhaust as before stated,and pressure is gradually exhausted from the chamber 52 above piston 53,thereby opening .valve 56 and venting the brake cylinders ofthe secondor following engines voir. Cock 91 in the train pipe connection 5is'closed. Pressure leaks through the valve 7 To release the" brakevalve, or in case a hose bursts, the

heavy and rapid reduction of pressure in the train pipe causes thepiston 80 to move over and establish communication from the mainreservoir through the double heading valve 76 and connection 84 to thepipe 11 and thebrake cylinders. Valve 56 is closed, and after thepressure has equalized into the brake cylinders through the reducingvalve 62, check valve 61 seats and prevents the return of pressure fromthe brake cylinders. The pressure in the main reservoir of the enginewill hold the piston 80 downwardly and also keep the valve 56 closed,thereby preventing loss of air from the brake cylinders through the ventport 59.

After a-service application the brakes are released by increasing trainpipe pressure in the usual manner to move the piston 80, close valve 81and open valve 56. Communication is then cut off between the mainreservoir and brake cylinder pipe 11, but the exhaust from the brakecylinder pipe through the engineersibrake valve releases pressure fromabove the piston 53 and opens the brake cylinders to exhaust throughvalve 56 and exhaust port 59. The exhaust from the brake cylinder pipeand chamber 52, through the engineers brake valve, produces a whistlingnoise, which in double heading, warns the engineer on the second orfollowing engines, of any application of the brakes, either bymanipulation of the engineers brake valve on the leading engine,orautomatically in case a hose bursts or the train parts.

In double heading, if the engineer of a second or following enginedesires to apply his engine and tender brakes he may do so byturning hisbrake valve handle to the second or straight air application position.

In this case pressure is admitted from the, main reservoir to the enginebrake cylinders by way of ports 33, 21, 19 and pipe 11. After the brakeshave been applied they may be held applied by turning the brake valvehandle to straight air lap position. The engineer may then release hisbrakes by turning his brake valve handle to running position. Thisexhausts the pressure from above the piston in valve 51 by way of port20 and permits the brake cylinders to exhaust by way of the exhaustvalve 51, as before described.

The system described does away with the necessity for a special triplevalve and auxiliary reservoir upon the engine. It is so arranged thatthe engineer can apply the brakes either by straight air orautomatically. Also, it may be utilized in double heading, Withoutspecial adjustments of any cocks or valves, by merely placing the brakevalve on the second or following engines in running position, to openthe limited exhaust from the brake pipe to the atmosphere. Moreover, itembodies simple means for utilizing the main reservoir substantially asan ordinary auxiliary reservoir in case the engine is double heading,pressure being maintained in the main reservoir of the second andfollowing engines, from the train pipe and the main reservoir on theleading engine, so that the brakes are rendered effective on all engineswithout the necessity of a special triple and auxiliary reservoir. Thesystem also takes care of emergency applications, or in case a hosebursts, without the liability of loss of pressure from the brakecylinders or main reservoir. It also enables the engineer on the secondor following engines to apply the brakes automatically in case ofnecessity and warns him of all applications of the brakes by othermeans.

The apparatus is extremely simple and comprises less apparatus than hasbeen necessary in prior systems for efi'ecting the same results. It mayalso embody apressure controlling valve, an accelerating valve and atrain pipe vent valve of the character shown in the prior patent toDukesmith referred to, although this is not essential.

What I claim is r 1. In an air brake system, the combination of a mainreservoir, a brake cylinder, an engineers brake valve, valve mechanismarranged upon variations in train pipe pressure to control communicationbetween the main reservoir and brake cylinder, a valve between the mainreservoir and brake cylinder, and a movable abutment cooperating withsaid valve and controlled by main reservoir pressure and arranged uponheavy reductions in train pipe pressure to hold said valve open.

2. In an air brake system, the combination of a main reservoir, a brakecylinder, an engineers brake valve, valve mechanism arranged uponvariations in train pipe pressure to control communication between themain reservoir and brake cylinder, a valve between the main reservoirand brake cylinder, and a movable abutment cooperating with said valveand controlled by main reservoir pressure and arranged upon servicereduction in train pipe pressure to limit the brake cylinder pressureand upon heavy reduction in train pipe pressure to hold said valve open.

In testimony whereof, I have hereunto set my hand.

PETER WERTZ.

Witnesses ELBERT L. HYDE, MILTON D. HAYS.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

